Convert channel counts to size_t.

webrtc/modules/audio_coding/neteq/include/neteq.h

Index: webrtc/modules/audio_coding/neteq/include/neteq.h
diff --git a/webrtc/modules/audio_coding/neteq/include/neteq.h b/webrtc/modules/audio_coding/neteq/include/neteq.h
index abe09a364b4e08ebb9fa9575b0ac1794d12ecc08..13222239708028e7b186a7791c7e55a8ec2d4173 100644
--- a/webrtc/modules/audio_coding/neteq/include/neteq.h
+++ b/webrtc/modules/audio_coding/neteq/include/neteq.h
@@ -171,7 +171,7 @@ class NetEq {
   // The speech type is written to |type|, if |type| is not NULL.
   // Returns kOK on success, or kFail in case of an error.
   virtual int GetAudio(size_t max_length, int16_t* output_audio,
-                       size_t* samples_per_channel, int* num_channels,
+                       size_t* samples_per_channel, size_t* num_channels,
                        NetEqOutputType* type) = 0;
 
   // Associates |rtp_payload_type| with |codec| and |codec_name|, and stores the